1. Field of the Invention
This invention relates to semiconductor processing, and more particularly to wafer flow and recipe editing for control of semiconductor processing equipment.
2. Description of the Related Art
The fabrication of semiconductor devices requires a large number of discrete processing steps to produce a complete semiconductor device. Specifically, a plurality of semiconductor devices usually begin as a single wafer of silicon and undergoes multiple processing steps such as epitaxial growth, resist development, etching, doping, etc. Wafers are generally fabricated together in batches of wafers called “lots” or “runs.” The fabrication process creates an array of semiconductor devices on each wafer. At the completion of the wafer processing, the wafers are tested to determine circuit functionality, and may then be separated into individual semiconductor devices.
In such typical semiconductor processes, each of the various wafer processing steps is performed at a specific processing station or unit. The processing tool is provided with information representing a series of process flow steps and recipes that control a track of the tool and direct the wafer through the processing steps. The wafer flow is a logical sequencing of the wafer through the track's processing modules (or units) in a time efficient manner, and the recipe determines what (e.g., time, temperature, etc.) occurs at each step. For example, the flow determines the order of processing steps through a processing tool, and the recipe specifies various processing parameters such as temperature, pressure, and gas flow, which are used during the set-up and operation of a processing station. The flow and recipe together form a set of processing instructions that relate both a particular process station nd a particular processing step.
A flow has line numbers, flow numbers, unit numbers, and recipe numbers associated with each step in the process. To maximize the speed of processing the track may include several identical processing units referred to as duplicate units. For example, wafers may be placed in duplicate units, but will receive the same processing therein. A single processing unit on a track is referred to a unique unit. The processing speed of the tool depends, in part, on each module's processing speed. In general, slower modules have duplicates in order to increase the availability of that particular processing unit, whereby the track wafer throughput will increase, and decrease the overall lot or run processing time. Generally, the processing of wafers requires multiple steps, and runs several processing stations in parallel. This requires the track controller of a processing tool to store and manipulate many flows and recipes for processing the wafers.
Editing flows and recipes on known processing tools is done at the processing tool controller. Editing recipes at the processing tool controller requires that the processing tool be taken off-line because editing a recipe during production can cause faulty processing of the wafer and defects in the final product. When a processing tool is taken off-line valuable production time is lost. Consequently, reducing the down time of semiconductor processing equipment is of high importance. Therefore, a method to edit flows and recipes remotely of the various processing tools and without the need for taking the processing tools off-line is desired.
A further problem with existing track editors is that it is difficult and time consuming to compare recipe files of the track controller with the master track files to ensure the proper recipes are running on a given processing tool. It may take up to 8 hours per week to manually verify recipe contents of a typical track system with a master copy. In addition to employing someone to ensure proper recipe contents, this down time of the processing tool is a costly burden upon the output production.
Further, current track editors have limited intelligence that may lead to costly errors when editing recipes. For example, a recipe may contain several steps in the processing procedure. When deleting or adding a step in a recipe or flow, existing editors require operators to manually update line numbers and/or flow line steps. Manually updating the line numbers and/or flow line steps is a time consuming task and can lead to costly errors in the fabrication of semiconductor devices.
Existing editors also fail to provide the ability to easily manipulate flows and recipes. For example, a user cannot copy and rename files without the need of an empty recipe slot in the editor, whereby the recipe is copied to the empty slot with a different name. Finally, existing editors must be edited, and recipes input into, at the processing tool itself.
Thus, the present inventors have identified that what is desired is a remote track editor that allows users to remotely edit and import/export process flows and recipes of multiple semiconductor processing tools. Further, it would be desired that such an editor allow sophisticated manipulations of the flows and recipes. For example, the ability to renumber line and flow step modules during an editing process, and to easily rename, copy, print, and compare recipes side-by-side in a Windows multitasking and network environment is desired.